Installing the French language

I want to be able to provide a dashboard in French for one of my sites in a multisite setup. I downloaded the plugin and started going through the files looking for the ones relating to French. First of all, I'm not certain which ones those are - I assume it's everything with "fr" in it. But the admin and network admin collection of files don't seem to have any French versions in them. I'm also not sure if I'm doing this right. Which of the files in the folder are required?